Ratchet mechanism for saw-mill set-works



(No Model.) 2 Sheets-Sheet 1.

W. F. PARISH.

RATCHET MECHANISM FOR SAW MILL SET WORKS.

No. 379,656. Patented Mar. 20, 1888.

WZYneJJeJ. Inv/rn?07' N PUERS. Phblwhlnograpber. Walhmgwn. D. C.

(No Model.) 2 Sheets-Sheet 2.

W. F. PARISH.

RATGHET MECHANISM FOR SAW MILL SET WORKS. No. 379,656. Patented Mar. 20,1888.

,,Gu -Q ans-aw UNITED STATES PATENT OFFICE.

XVILLIAM F. PARISH, OF MINNEAPOLIS, MINNESOTA.

RATCHET MECHANISM FOR SAW-MILL SET-NORKS.

SPECIFICATION forming part of Letters Patent No. 379,656, dated March20, 1888.

Application filed May 1886. Serial No 203,065.

To, aZZ whom it may concern.-

Be it known that I, \VILLIAM F. PARISH, of Minneapolis, in the county ofHennepin and State of Minnesota, have invented certain Improvements inRatchet Mechanism for Saw- Mill Set-Works, of which the following is aspecification.

This invention relates to improvements in that class of ratchetmechanisms that are used for operating the set-shafts of sawmillcarriages; and my invention consists, generally, in the construction andcombination hereinafter described, and pointed out in the claim.

In the accompanying drawings, forming part of this specification, Figure1 is a side elevation of a ratchet mechanism constructed in accordancewith my invention. Fig. 2 is a partial side elevation of theratchet-wheel and section of the pawl-carriers. Fig. 3 is a plan of oneof the carriers with the top plate removed. Fig. 4 is a transversevertical section of one of the carriers and a portion of the wheel. Fig.5 is a transverse vertical section of the carriers and a portion of thewheel, showing a modified arrangement. Figs. 6 and 7 are details.

The ratchet-wheel may be mounted directly on the set-shaft of thecarriage in the usual way, or it may be mounted 011 a counter-shaft thatis connected by suitable gearing with the set-shaft, as shown in myPatent No. 352,838, granted November 16, 1886.

In the drawings, 2 represents the shaft to which the ratchet'wheel issecured. This shaft is mounted in suitable bearings upon the sawmillcarriage. The operating-lever 3 is'secured to a rock-shaft, 5, mountedin suitable bearings and provided with crank-arms 7 and 9. An are orquadrant, 11, which is preferably provided with pins or stops 15, issecured to the frame in position so that the lever or an attachmentthereon strikes against one of the pins as the lever is moved in eitherdirection.

The ratchet-wheel 13 may be of any ordinary form or construction. It hasthe usual ratchet-teeth and may be provided upon each side with anannular groove, 17, located near its edge.

The mechanism is provided with two pawlcarriers that are secured to thewheel, and each holdsa series of sliding pawls or dogs, any

springs in place thereof.

(No model.)

one of which is adapted to engage with the teeth of the ratchet-wheel.The pawl-carriers each consist of a box or frame, 21, having a series ofopenings, 23, in each of which is placed a sliding dog, 25. The carriersare formed with suitable bearings for the sliding dogs, preferably atthe ends, and in the center of each dog, as shown in Fig. 3. A plate,27, is provided for each carrier. This plate fits over the top of thecarrier and holds the dogs in place. The weight of the dogs causes themto slide downward in the carriers into position to engage the teeth ofthe ratchet. I prefer,- however, to provide aspring, 29, for each dog,that tends to press it down into engagement with the ratchet-wheel.These springs are arranged in the carrier between the dogs and the plate27. The springs 29 are shown as elliptic springs. I may, however, usesuitable coiled The sliding dogs and the teeth of the ratchet-wheel arepreferably differentially spaced, so that a fine adjustment of the wheelmay be made.

I prefer to provide four dogs for each carrier and to arrange them so asto divide into quarters the spaces of the teeth. The four dogs may bearranged to cover five teeth on the wheel, and in order that there maybe considerable metal in the carrier between every two dogs I prefer toarrange them as shown in Fig. 2. As here shown, the middle space, orthat between the second and third dogs, is equal to one andthree-quarters tooth of the wheel, and the other spaces between the dogsare equal to one and a half tooth of the wheel. \Vlien the first dog inthe carrier is in engagement with the ratchet, as shown at the righthandside of Fig. 2, the second dog is one-half of a space from the point ofa tooth, the third one-quarter, and the fourth three-quarters. Thereare, in effect, therefore, four dogs to each tooth of the ratchet-wheel,which allows the ratchet mechanism to be set by quarter-divisions of theteeth. I do not, however, confine myself to this number of dogs for eachcarrier, as one, two, three, or more dogs may be used without departingfrom my invention. When two or three dogs are used, they are arranged soas to divide the ratchet-teeth into halves or thirds, and so on for anyother number of dogs.

Each of the carriers is provided with keys 33, that fit into the grooves17 on the sides of the ratchet-wheel'and hold' the carriers in place.The carriers are also connected by rods 35 37 with the crank-arms 7 and9. The back carrier is preferably connected to its crankarm 9 by asingle connecting-rod, 37, that is pivoted to the crank-arm and to oneend of the carrier, while the other is connected by two connecting-rods,35, pivoted upon each side thereof and passing uponopposite sides of theback carrier, to the crankarm 7.

The ratchet mechanism is operated by moving the lever 3 in eitherdirection, thereby advancing one of the pawlm-arriers and receding theother. The ratchet-wheel is thereby continuously rotated.

In some instances the carriers may be connected by carrier-arms 43 withthe shaft, and thereby be held upon the edge of the wheel, and thegroove 17 and keys 33 may be dispensed with, as shown in Figs. 2, 6, and7.

43 of the forward carrier extend outside of the arms of the backcarrier, as shown in Fig. 7, so that the arms do not interfere when thecarriers approach each other.

Instead of arranging one carrier in advance of the other, I may arrangethem side by side, as shown in Fig. 5, and connect each one with theshaft by the carrier-arm 43. In this instance the width of each carrieris equal to about one-half the width of the face of the wheel. I

This ratchet mechanism possesses many advantages over those commonlyused. The mechanism is very strong, as with this mode of spacing thedogs a fine adjustment may be obtained without using fine teeth andsmall dogs. The mechanism is also inexpensive and the dogs and springsare substantially inclosed on all sides and protected from dust anddirt.

Another great advantage is in the wearing qualities of the mechanism. Asthe dogs are brought at all times when at work fairly in contact withthe faces of the teeth, there is very little wear, and what wear thereis does not affect their operation, as when their ends become worn thedogs drop down farther in the carriers and engage the teeth asbefore.Moreover, two of the dogs maybe removed when there are four in thecarrier, and the ratchetteeth will then be divided into halves by thetwo remaining dogs; or all but one of the dogs may he removed and thedivision will then be simply that made by the ratchet-teeth.

When the ratchet wheel is placedon the setshaft, a simple cam may beused to slide the teeth back into the carrier when the set-shaft istoibe reversed. When the carriers are thus arranged, the arms I claim asmy invention- Thecombination, with the ratchet-wheel, of

the pawl-carrier arranged over the face of the wheel and having-theseries of openings 23 extending through it, the cap-plate secured uponsaid carrier and covering all of said openings, the series of slidingdogs arranged in said openings, and the springs arranged in saidopenings between said dogs and said plate, all substantially asdescribed.

In testimony whereof I have hereunto set my hand this 20th day of May,1886.

WILLIAM F. PARISH.

In presence of-- A. 0. PAUL, R. H. SANFORD.

